--- title: "How Do Failed SPF Or DKIM Checks On IONOS Affect Email Delivery And Sender Reputation? | DMARC Report" description: "Learn how failed SPF or DKIM checks on IONOS can affect email delivery, authentication, inbox placement, and sender reputation." image: "https://dmarcreport.com/og/blog/how-failed-spf-dkim-checks-ionos-affect-email-delivery-reputation.png" canonical: "https://dmarcreport.com/blog/how-failed-spf-dkim-checks-ionos-affect-email-delivery-reputation/" --- Quick Answer Failed SPF or DKIM checks on IONOS can reduce email authentication success, increase spam filtering, and hurt sender reputation. Fix DNS records, alignment, and authentication errors to improve deliverability and inbox placement. Share [ ](https://www.linkedin.com/sharing/share-offsite/?url=undefined%2Fblog%2Fhow-failed-spf-dkim-checks-ionos-affect-email-delivery-reputation%2F "Share on LinkedIn") [ ](https://twitter.com/intent/tweet?text=How%20Do%20Failed%20SPF%20Or%20DKIM%20Checks%20On%20IONOS%20Affect%20Email%20Delivery%20And%20Sender%20Reputation%3F&url=undefined%2Fblog%2Fhow-failed-spf-dkim-checks-ionos-affect-email-delivery-reputation%2F "Share on X/Twitter") [ ](https://www.facebook.com/sharer/sharer.php?u=undefined%2Fblog%2Fhow-failed-spf-dkim-checks-ionos-affect-email-delivery-reputation%2F "Share on Facebook") [ ](https://reddit.com/submit?url=undefined%2Fblog%2Fhow-failed-spf-dkim-checks-ionos-affect-email-delivery-reputation%2F&title=How%20Do%20Failed%20SPF%20Or%20DKIM%20Checks%20On%20IONOS%20Affect%20Email%20Delivery%20And%20Sender%20Reputation%3F "Share on Reddit") [ ](mailto:?subject=How%20Do%20Failed%20SPF%20Or%20DKIM%20Checks%20On%20IONOS%20Affect%20Email%20Delivery%20And%20Sender%20Reputation%3F&body=Check out this article: undefined%2Fblog%2Fhow-failed-spf-dkim-checks-ionos-affect-email-delivery-reputation%2F "Share via Email") ![Failed SPF or DKIM Checks](https://media.mailhop.org/dmarcreport/how-to-create-dmarc-record-5207-1790587769350.jpg) ## Try Our Free SPF Checker Instantly analyze any domain's SPF record - check syntax, count DNS lookups, and flag errors. [ Check SPF Record → ](/tools/spf-checker/) On IONOS, when SPF or DKIM checks fail, messages are usually accepted but tagged and routed to spam/quarantine unless an enforcing DMARC policy (p=quarantine/reject) is in place—in which case IONOS and most downstream receivers will quarantine or outright reject—and repeated authentication failures measurably erode domain/IP sender reputation, triggering stricter filtering, rate limits, and potential **blocks across providers**; use DMARCReport to detect, fix, and monitor these failures before they damage deliverability. ## Context and Background: Why SPF/DKIM on IONOS Matter Email authentication hinges on three related standards: SPF (validates the sending IP), DKIM (validates message integrity and domain identity via a cryptographic signature), and DMARC (enforces policy when SPF and/or DKIM fail and ensures alignment with the visible From domain). IONOS, like other large [mailbox providers](https://en.wikipedia.org/wiki/Mailbox%5Fprovider) and hosting platforms, evaluates all three for inbound messages and enables hosted domains to publish DNS needed for outbound authentication. In practice, a single failed SPF or DKIM check does not always equal a delivery block; the outcome depends on DMARC policy and total spam score. _However, repeated failures—especially when aligned authentication fails under DMARC—are strong, negative signals that degrade reputation_. DMARCReport closes the loop by turning raw DMARC aggregate and forensic data from IONOS and other receivers into actionable insights, so you can fix misconfigurations, track reputation, and steadily raise inbox placement. Below, we go deeper on IONOS-specific handling, how DMARC drives outcomes, and what to configure in **DNS to avoid failure**, with concrete examples, pitfalls, and recovery strategies—each tied back to how DMARCReport accelerates diagnosis and prevention. ## How IONOS Handles SPF/DKIM Failures Inbound ### What Happens on Failure: Reject, Quarantine, or Tag? - **By default (no enforcing DMARC)**: - An SPF or DKIM failure does not automatically mean an email will be rejected. The receiving server may classify the message as spam, quarantine it, or reject it depending on its filtering policies and the domain’s [DMARC policy](https://dmarcreport.com/dmarc-policy/). - IONOS adds headers that declare the result and contribute to filtering. - With enforcing DMARC p=quarantine/reject and alignment failure: - **p=quarantine**: IONOS and most downstream receivers are likely to place the message in Spam or quarantine. - **p=reject**: With a DMARC policy of p=reject, the receiving server is instructed to reject messages that fail DMARC. The exact handling depends on the receiving provider’s implementation and policies. #### Headers You’ll See - **Authentication-Results**: spf=pass|fail; dkim=pass|fail; dmarc=pass|fail (with alignment notes) - **Received-SPF**: Details the mechanism that passed/failed - **DKIM-Signature**: Present on the message if signed; receivers add **results in Authentication-Results** - **X-Spam-Status / X-Spam-Flag**: Spam scoring that often increases on SPF/DKIM failures **DMARCReport connection**: DMARCReport ingests the resulting DMARC aggregate (RUA) and optional forensic (RUF) reports from IONOS and other ISPs, correlates them with these header outcomes, and flags which failures were alignment-related (policy-tripping) versus benign (non-aligned sources such as forwarders), so you can fix what matters first. ### Logs and Evidence IONOS mailbox users don’t typically get raw [mail transfer agent (MTA)](https://www.techtarget.com/whatis/definition/mail-server-mail-transfer-transport-agent-MTA-mail-router-Internet-mailer) logs for inbound, so headers are your ground truth. For delivery decisions at other providers (e.g., Gmail, Outlook), their “Show original” views will also include Authentication-Results that match what they observed. **DMARCReport connection**: Even without MTA logs, DMARCReport reconstructs the delivery posture using per-source RUA data and forensic samples (when enabled), giving you a near-log-level map of authenticating sources and failures by IP, “From” domain, and DKIM selector. ![DMARC Interactions: How Failures Escalate or De-escalate](https://media.mailhop.org/dmarcreport/dmarc-check-8506-1790587847206.jpg) ## DMARC Interactions: How Failures Escalate or De-escalate ### DMARC’s Enforcement Logic at IONOS and Beyond - DMARC passes if either: - **SPF passes with alignment** (the envelope-from/Return-Path domain aligns with the visible From domain per aspf mode), or - DKIM passes with alignment (d= domain matches the From domain per adkim mode). - If both fail to align, the message is dmarc=fail, and the receiver follows the sender’s policy p=none|quarantine|reject (or sp= for subdomains). _IONOS honors DMARC; if your domain publishes p=reject and alignment fails, expect rejections or silent discards at many receivers._ If p=none, messages are typically delivered but negatively scored; aggregate/forensic reports are still generated. **DMARCReport connection**: Set RUA/RUF addresses to DMARCReport (e.g., `rua=mailto:aggregate@rua.dmarcreport.example`; `ruf=mailto:forensic@ruf.dmarcreport.example`) to centralize multi-ISP telemetry. DMARCReport’s alignment analyzer explains exactly which side (SPF or DKIM) saved or sank a message and models the impact if you move from p=none to p=quarantine/reject. ### Impact on Downstream Handling and Reporting - Aggregate (RUA) reports reflect per-receiver pass/fail and alignment; forensic (RUF) reports (if enabled and supported) provide redacted samples on failure. - When you forward mail or use [Email Service Provider (ESP)](https://business.adobe.com/blog/basics/email-service-providers), some receivers will salvage with DKIM even if SPF fails; others rely heavily on DMARC alignment. Over time, consistent failures increase spam foldering. **DMARCReport connection**: DMARCReport trends your domain’s pass/fail rates by receiver (e.g., Gmail vs Outlook vs Yahoo) and quantifies the before/after **effect of DNS changes**, helping you choose the right moment to tighten your DMARC to quarantine/reject. ## DNS on IONOS: SPF/DKIM for IONOS SMTP vs Third‑Party ESPs ### Recommended SPF for IONOS SMTP - Typical pattern when sending via IONOS-hosted mail: - **SPF TXT at root**: `v=spf1 include:_spf.perfora.net include:_spf.kundenserver.de ~all` - Use \~all (softfail) while testing; move to -all when fully audited. - **Note**: IONOS operates regionally; confirm current include mechanisms in your IONOS panel/docs. Common pitfalls: - Duplicating multiple SPF records (must be exactly one TXT record for SPF). - Exceeding the 10-DNS-lookup limit due to nested includes. - Using ptr or mx mechanisms unnecessarily (increase lookups/spam score). **DMARCReport connection**: DMARCReport’s SPF Evaluator simulates [DNS lookups](https://www.digicert.com/faq/dns/how-does-dns-lookup-work), warns when you’re near the 10-lookup limit, and recommends safe “flattening” strategies that won’t break vendor IP agility. ### DKIM on IONOS - Generate and publish a 2048-bit DKIM key. - Selector practices: - Use clear, purpose-tied selectors (e.g., k1 for transactional, m1 for marketing). - TXT record at `selector._domainkey.example.com` with the public key (p=…). - Watch TTL/propagation (often 5 minutes to several hours). **Avoid multiple conflicting** TXT records at the same selector. **DMARCReport connection**: The DKIM Inventory in DMARCReport enumerates active selectors seen in the wild, flags short keys (<2048), keyed-off domains that never sign, and warns when multiple selectors conflict or go dark after rotation. ### Third‑Party ESPs (SendGrid, Mailchimp, etc.) - Prefer DKIM and a custom return-path with the ESP’s domain to minimize SPF coupling. - Optionally include the ESP’s SPF only if they require it for bounce handling from your root domain; otherwise, keep SPF tight to reduce lookup load. - Align DKIM (d=) with your visible From domain for DMARC. **DMARCReport connection**: _Source Attribution groups DMARC reports by provider, surfacing which ESPs are failing alignment and why (e.g., DKIM not enabled, wrong selector, envelope-from misaligned)_. ## Why Forwarding and Lists Break Things (and How to Fix It) ### Forwarding and SPF Forwarding commonly fails SPF because the forwarder sends from its own IP while keeping your From domain. Mitigation: [SRS (Sender Rewriting Scheme)](https://forwardmx.net/blog/sender-rewriting-scheme/) rewrites the envelope-from so SPF can pass at the next hop. - If you control the forwarder (e.g., a gateway, list server), enable SRS. - If forwarding through a provider that doesn’t implement SRS, **rely on DKIM alignment** to carry DMARC. **DMARCReport connection**: DMARCReport identifies high SPF-fail/forwarding patterns by receiver and recommends SRS on specific relays. It also quantifies how many failures are “salvaged” by DKIM, justifying operational focus. ### Mailing Lists and DKIM Mailing lists often alter subject/body, breaking DKIM. Use DMARC-friendly list modes: - Add comments as separate [MIME](https://en.wikipedia.org/wiki/MIME) parts to preserve DKIM. - Or rewrite From (per RFC 7960) to a list domain to avoid DMARC failure. **DMARCReport connection**: The Forensic Viewer highlights which list modifications break DKIM and suggests From-rewrite or MIME-preserve configurations based on observed failures. ### ARC as an Additional Signal Authenticated Received Chain (ARC) can preserve upstream authentication results through intermediaries. Not all receivers **fully trust ARC**, but it helps. **DMARCReport connection**: DMARCReport marks traffic with ARC-Seal/ARC-Message-Signature and correlates whether ARC presence improves inbox rates at specific receivers. ![Reputation Impact: What Repeated Failures Do Over Time](https://media.mailhop.org/dmarcreport/dmarc-lookup-5108-1790587905779.jpg) ## Reputation Impact: What Repeated Failures Do Over Time Repeated SPF, DKIM, and DMARC alignment failures can negatively affect email deliverability and sender reputation. Persistent authentication problems may contribute to increased spam placement, stricter filtering, throttling, or message rejection, depending on the receiving provider and the sender’s overall reputation. The impact can vary by provider, sending volume, IP reputation, domain reputation, authentication configuration, and message content. For this reason, monitoring authentication results over time is more useful than evaluating a single failure. DMARCReport helps identify recurring authentication failures, unauthorized sending sources, and alignment problems across receiving providers. Monitoring these trends allows organizations to identify configuration issues, measure improvements after DNS changes, and determine when their domain is ready for stronger [DMARC enforcement](https://dmarcreport.com/blog/fixing-dmarc-enforcement-for-smaller-and-emerging-brands/). How big providers react: - **Gmail**: Sensitive to domain-level authentication; sustained failures reduce domain reputation and can trigger bulk [rate limiting](https://www.cloudflare.com/learning/bots/what-is-rate-limiting/). - **Outlook (Microsoft 365)**: Mix of IP and domain reputation; repeated failures, especially from shared IP pools, escalate **throttling and content scrutiny**. - **Yahoo**: Strongly enforces bulk sender requirements (SPF, DKIM, DMARC); alignment failures increase spam foldering quickly. **DMARCReport connection**: _The Reputation Timeline aligns failure percentages with spam-folder rates and receiver-specific disposition trends, so you can validate that fixes are improving outcomes and catch regressions fast_. ## Troubleshooting on IONOS: Tools, Steps, and Tests ### Step-by-Step Diagnostic Flow 1. **Inspect a failing message’s headers**: - Authentication-Results, Received-SPF, DKIM-Signature, X-Spam-Status. 2. **Validate DNS in the IONOS DNS Control Panel**: - Exactly one SPF record; includes correct; no typos. - DKIM TXT present at `selector._domainkey` with a valid, complete p= key. 3. **Check lookup budget**: - Count SPF DNS mechanisms; aim for ≤8 to leave a safety margin. 4. **Send controlled tests**: - To Gmail/Outlook/Yahoo test inboxes; compare “Show original” outcomes. 5. **Verify with external tools**: - dig/nslookup; dkimverify/dkimpy; SPF/DKIM validators; DMARCReport instant checks. **DMARCReport connection**: The guided “Fix-It” Playbooks in [DMARCReport](https://dmarcreport.com/) parse recent failures and generate a prioritized to-do list (e.g., “Enable DKIM on IONOS for selector k1; remove duplicate SPF record; reduce lookups from 12 to 8 by consolidating ESP includes”). ### Common SPF Errors on IONOS and Corrections - **Exceeding 10 lookups**: Flatten or consolidate includes; **drop unused vendors**. - **Syntax mistakes**: Missing spaces, uppercase “ALL”, or stray quotes; fix to valid SPF grammar. - **Wrong includes**: Using legacy or region-mismatched includes; confirm current IONOS includes. - **Multiple SPF records**: Merge into one. **DMARCReport connection**: The SPF Change Simulator previews how proposed edits affect pass/fail across observed sources and flags any residual over-budget risks before you publish. ### DKIM-Specific Issues on IONOS - **Wrong selector in DNS vs signing config**: Ensure the selector in your MTA matches the published TXT. - **Key length too short**: Upgrade to 2048-bit keys; rotate quarterly or biannually. - **TTL/prop delays**: Allow time; don’t rotate both old/new keys simultaneously without overlap. - **Conflicting keys**: Remove stale TXT for the same selector after cutover. Safe rotation procedure: 1. Publish new selector (e.g., k2) with a 2048-bit key; keep old (k1) active. 2. Update IONOS/ESPs to sign with k2. 3. Monitor with DMARCReport for 7–14 days; confirm passes at all receivers. 4. Retire k1 from signing; remove k1 TXT after a safety window. **DMARCReport connection**: The Selector Health dashboard confirms which selectors are actively passing, warns of stale keys still observed at receivers, and provides rotation-readiness checks. ## Use-Case Best Practices: Transactional vs Marketing - **Segregate by subdomain**: - transactional.example.com for product traffic; news.example.com for marketing. - Distinct DKIM selectors and, if possible, distinct IPs/providers. - **Strict alignment**: - adkim=s and aspf=s for transactional to minimize spoofing; relaxed for marketing if needed for list compatibility. - **DMARC policy**: - Start p=none with rua to DMARCReport; move transactional to p=reject sooner; keep **marketing at p=quarantine** during optimization. **DMARCReport connection**: _Subdomain Reporting and Per-Selector Analytics let you watch each stream’s performance independently, so tightening transactional policy doesn’t penalize marketing experiments_. ![Remediation and Ongoing Monitoring Strategy](https://media.mailhop.org/dmarcreport/dmarc-record-5206-1790587964499.jpg) ## Remediation and Ongoing Monitoring Strategy - **Phase 1**: Monitor - Publish DMARC p=none; add rua/ruf to DMARCReport. - Set DMARCReport alerts for >2% failure spikes, new unauthorized sources, and selector lapses. - **Phase 2**: Fix and harden - Correct SPF/DKIM issues; implement SRS on forwarders you control; adopt DMARC-friendly list modes. - Move to p=quarantine after 30 days of sub-2% failures; then to p=reject for high-integrity streams. - **Phase 3**: Sustain - Rotate DKIM keys on schedule; audit [SPF](https://dmarcreport.com/what-is-spf/) quarterly; review DMARCReport trendlines monthly. - Consider BIMI once DMARC is at enforcement and reputation stabilizes. **DMARCReport connection**: Automated weekly executive summaries and anomaly alerts keep teams aligned, while API/webhooks let you route critical events into Slack, Teams, or SIEM. ## FAQs ### Does IONOS always reject emails when SPF or DKIM fail? No. Without an enforcing DMARC policy, IONOS typically accepts the message but increases its spam score; with DMARC p=quarantine/reject and alignment failure, **quarantine or rejection** is likely. DMARCReport shows which receivers enforced which policy for your traffic. ### Which headers show SPF/DKIM/DMARC results on IONOS messages? Look for Authentication-Results (spf=, dkim=, dmarc=), Received-SPF, DKIM-Signature, and spam headers like X-Spam-Status/X-Spam-Flag. DMARCReport correlates these with RUA/RUF data to surface root causes. ### How long should I wait after publishing DKIM on IONOS before expecting passes? Propagation can take minutes to hours depending on [Time to live (TTL)](https://www.ibm.com/think/topics/time-to-live) and [DNS caching](https://www.geeksforgeeks.org/computer-networks/what-is-dns-caching/). Use DMARCReport’s live checks and watch for passes at major receivers for 24–48 hours before tightening policy. ### What if I use Mailchimp/SendGrid but host DNS and mailboxes at IONOS? Publish the **ESP’s DKIM and custom** return-path records; keep your SPF under 10 lookups and avoid unnecessary includes. DMARCReport will attribute failures to the ESP and guide exact record changes. ### Can ARC or SRS fully eliminate forwarding-related failures? _SRS can salvage SPF; ARC can help receivers trust upstream authentication, but neither is guaranteed everywhere_. Aim for DKIM alignment and DMARC monitoring with DMARCReport to quantify effectiveness. ![Preventing IONOS Email Authentication Failures & Protecting Domain Reputation](https://media.mailhop.org/dmarcreport/what-is-dmarc-8405-1790588034537.jpg) ## Conclusion: Prevent Failures, Protect Reputation—With DMARCReport Failed SPF or DKIM on IONOS typically leads to spam tagging unless DMARC demands enforcement, but repeated failures will degrade reputation and [inbox placement](https://www.activecampaign.com/blog/inbox-placement) across major providers. The fastest, safest path to deliverability is consistent alignment, careful DNS hygiene, and policy you can trust. DMARCReport turns raw DMARC feedback into decisive action: it inventories your authenticating sources, spots SPF over-budget and DKIM/selector issues, models the impact of policy changes, and alerts you before small mistakes become **big reputation problems**. Add DMARC rua/ruf to DMARCReport today, fix what’s broken with guided playbooks, and move to enforcement with confidence—so your messages land where they belong: the inbox. ![Brad Slavin](https://media.mailhop.org/dmarcreport/images/team/brad-slavin.jpg) [ Brad Slavin ](/authors/brad-slavin/) General Manager General Manager of DuoCircle. Product strategy and commercial lead for DMARC Report's 2,000+ customer base. [LinkedIn Profile →](https://www.linkedin.com/in/bradslavin) ## Take control of your DMARC reports Turn raw XML into actionable dashboards. Start free - no credit card required. [Start Free Trial](https://app.dmarcreport.com/signup?plan=free) [Check Your DMARC Record](/tools/dmarc-checker/) Scan Your Domain Now Instantly scan your domain for DKIM, SPF, and DMARC issues Check My Domain Share this article [ ](https://www.linkedin.com/sharing/share-offsite/?url=https%3A%2F%2Fdmarcreport.com%2Fblog%2Fhow-failed-spf-dkim-checks-ionos-affect-email-delivery-reputation%2F) [ ](https://twitter.com/intent/tweet?text=How%20Do%20Failed%20SPF%20Or%20DKIM%20Checks%20On%20IONOS%20Affect%20Email%20Delivery%20And%20Sender%20Reputation%3F&url=https%3A%2F%2Fdmarcreport.com%2Fblog%2Fhow-failed-spf-dkim-checks-ionos-affect-email-delivery-reputation%2F) [ ](https://www.facebook.com/sharer/sharer.php?u=https%3A%2F%2Fdmarcreport.com%2Fblog%2Fhow-failed-spf-dkim-checks-ionos-affect-email-delivery-reputation%2F) Copy Related Articles - [ ![10 Reasons Why DKIM Fails](https://media.mailhop.org/dmarcreport/images/2022/04/dmarc-alignment-6379.jpg) 10 Reasons Why DKIM Fails Intermediate ](/blog/10-reasons-why-dkim-fails/) - [ ![cybersecurity news](https://media.mailhop.org/dmarcreport/dmarc-check-9711-1784029121308.jpg) Accenture Sourcecode Breached, JADEPUFFER AI Ransomware, GodDamn Disables Windows Intermediate ](/blog/accenture-sourcecode-breached-jadepuffer-ai-ransomware-goddamn-disables-windows/) - [ ![AppRiver SPF Record](https://media.mailhop.org/dmarcreport/dmarc-check-7224-1785846270575.jpg) AppRiver SPF Record: How To Set It Up (Owned By Zix) Intermediate ](/blog/appriver-spf-record-setup-guide-for-zix-email-security-platform/) - [ ![Cybersecurity ransomware news](https://media.mailhop.org/dmarcreport/dmarc-report-3120-1788259786008.jpg) Berlin Ransomware Extortion, McKesson Data Breach, Boston Scientific Disrupted Intermediate ](/blog/berlin-ransomware-extortion-mckesson-data-breach-boston-scientific-disrupted/) ## Related Articles [ Intermediate 4m 10 Reasons Why DKIM Fails Apr 19, 2022 ](/blog/10-reasons-why-dkim-fails/)[ Intermediate Accenture Sourcecode Breached, JADEPUFFER AI Ransomware, GodDamn Disables Windows Jul 14, 2026 ](/blog/accenture-sourcecode-breached-jadepuffer-ai-ransomware-goddamn-disables-windows/)[ Intermediate AppRiver SPF Record: How To Set It Up (Owned By Zix) Aug 4, 2026 ](/blog/appriver-spf-record-setup-guide-for-zix-email-security-platform/)[ Intermediate Berlin Ransomware Extortion, McKesson Data Breach, Boston Scientific Disrupted Sep 1, 2026 ](/blog/berlin-ransomware-extortion-mckesson-data-breach-boston-scientific-disrupted/) ```json {"@context":"https://schema.org","@type":"Organization","@id":"https://www.wikidata.org/wiki/Q138898167","name":"DMARC Report","url":"https://dmarcreport.com","logo":{"@type":"ImageObject","url":"https://dmarcreport.com/images/dmarcreport-logo.png"},"description":"DMARC reporting and email authentication management. 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DMARCReport shows which receivers enforced which policy for your traffic."}},{"@type":"Question","name":"Which headers show SPF/DKIM/DMARC results on IONOS messages?","acceptedAnswer":{"@type":"Answer","text":"Look for Authentication-Results (spf=, dkim=, dmarc=), Received-SPF, DKIM-Signature, and spam headers like X-Spam-Status/X-Spam-Flag. DMARCReport correlates these with RUA/RUF data to surface root causes."}},{"@type":"Question","name":"How long should I wait after publishing DKIM on IONOS before expecting passes?","acceptedAnswer":{"@type":"Answer","text":"Propagation can take minutes to hours depending on [Time to live (TTL)](https://www.ibm.com/think/topics/time-to-live) and [DNS caching](https://www.geeksforgeeks.org/computer-networks/what-is-dns-caching/). Use DMARCReport’s live checks and watch for passes at major receivers for 24–48 hours be..."}},{"@type":"Question","name":"What if I use Mailchimp/SendGrid but host DNS and mailboxes at IONOS?","acceptedAnswer":{"@type":"Answer","text":"Publish the **ESP’s DKIM and custom** return-path records; keep your SPF under 10 lookups and avoid unnecessary includes. DMARCReport will attribute failures to the ESP and guide exact record changes."}},{"@type":"Question","name":"Can ARC or SRS fully eliminate forwarding-related failures?","acceptedAnswer":{"@type":"Answer","text":"*SRS can salvage SPF; ARC can help receivers trust upstream authentication, but neither is guaranteed everywhere*. Aim for DKIM alignment and DMARC monitoring with DMARCReport to quantify effectiveness."}}]}] ``` ```json {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://dmarcreport.com/"},{"@type":"ListItem","position":2,"name":"Blog","item":"https://dmarcreport.com/blog/"},{"@type":"ListItem","position":3,"name":"Intermediate","item":"https://dmarcreport.com/intermediate/"},{"@type":"ListItem","position":4,"name":"How Do Failed SPF Or DKIM Checks On IONOS Affect Email Delivery And Sender Reputation?","item":"https://dmarcreport.com/blog/how-failed-spf-dkim-checks-ionos-affect-email-delivery-reputation/"}]} ```